A Comparison of Safety Culture Associated with Three Engineered Systems in Japan and the United States

The internationally reported nuclear criticality accident at JCO in Tokaimura, Japan has further eroded public confidence in nuclear energy, its related facilities and the (Japanese) government’s ability to handle such a crisis. The JCO accident marked the sixth nuclear-related incident since 1995. The existing state of “safety culture” is being questioned and re-evaluated at a national level. In this work the safety culture associated with engineered systems (ES) such as the automobile, commercial airplane and nuclear power plants (NPP) are evaluated based on a scale-analysis (SA), via proposition of two fundamental parameters called eigenmetrics. The identified eigenmetrics are time- (τ) and number-scales (N) describing both ES and human factors, at the individual and/or societal levels. The SA approach is appropriate because human perception of risk (POR), perception of benefit (POB) and level of (technology) acceptance (LOA) are inherently subjective, therefore “fuzzy” and rarely quantifiable in exact magnitude. POR expressed in terms of the psychometric factors “dread risk” and “unknown risk”, contain both time- and number-scale elements. The JCO accident, as well as auto-fatalities, commercial airline accidents and hypothetical NPP accidents are characterized in terms of τ, N and two additional derived parameters of relevance, Nτ and N/τ. We contend that LOA infers a POB at least two orders of magnitude larger than POR. The “amplification” influence of mass-media is also deduced as being 100 to 1000 fold the actual number of fatalities/serious injuries in a nuclear-related accident.